A Guide to Tooth Cracks and Fractures | 医療法人社団EPSDC

Introduction

Sometimes teeth feel sensitive or hurt when you bite, even with no cavities. One possible cause is a crack or fracture.
Small cracks are hard to notice at first, but if ignored they can lead to severe pain or even tooth extraction. That’s why “find it early, protect it early” matters.

New Basic 1: Stress is making cracks more common

Since COVID-19, reports show more tooth cracks. One reason is stress-related grinding and clenching (bruxism), both at night and during the day.
Even “perfect, untreated teeth” can crack—especially back teeth (premolars and molars) that take heavy biting forces.
Key idea: Stress → more clenching → excessive force on teeth → tiny cracks progress more easily.

New Basic 2: Teeth “age,” especially after your 40s

Dentin inside the tooth gets harder with age, but loses its flexibility (shock absorption).
When a tooth becomes harder and more brittle, repeated strong biting forces can make cracks deepen and spread faster.
Key idea: As you age, avoid overloading your teeth—don’t force yourself to chew very hard foods.

New Basic 3: Regular X-rays often don’t show cracks

In living teeth (with vital nerves), the chance of seeing a crack on standard 2D dental X-rays is reported to be very low.
Dentists combine special tests to diagnose cracks:
- Microscope/loupes: magnify to see fine cracks
- Transillumination: shine strong light to reveal crack lines
- Dye staining: color settles in crack grooves to make them visible
- Bite test: reproduce sharp pain when biting or releasing
- CBCT (3D dental CT): may not show the crack line itself, but can show 3D changes in the surrounding bone as clues
Key idea: “No problem on 2D X-ray” doesn’t always mean safe. If discomfort continues, get a detailed exam.

New Basic 4: The type of crack changes the urgency

From the crown (top of the tooth):
- Craze lines: surface lines in enamel; mainly cosmetic, low urgency
- Cracked tooth (CT): crack reaches dentin; sharp pain on biting, cold sensitivity
- Split tooth: crack progresses and the tooth splits into two parts
From the root side:
- Vertical root fracture (VRF): crack starts along the root; if it advances, the root can split (split root)
Key idea: Leaving a cracked tooth untreated lets bacteria enter, causing nerve inflammation and even splitting. Early detection and early treatment are critical.

New Basic 5: Don’t rush to extraction—cover and protect with cuspal coverage

Grinding away all cracked areas can weaken the tooth. A better option is cuspal coverage (onlay/crown) that covers the whole biting surface.
Covering the tooth blocks biting forces from prying the crack wider, and studies report higher tooth survival with this approach.
If you catch it early—before there’s a “deep, localized periodontal pocket” (meaning bone loss isn’t deep)—the chances of saving the tooth rise a lot.
When needed, precise sealing during root canal treatment or removing only the diseased root (root resection) can sometimes preserve part of the tooth.
Key idea: “Crack = immediate extraction” is not always true. Under the right conditions, the tooth can be saved.

Prevention and self-care you can start now

Wear a night guard (mouthpiece) during sleep to reduce grinding forces.
Get your bite adjusted so force doesn’t concentrate on just one tooth.
Don’t ignore warning signs: if sharp bite pain or lingering sensitivity continues, get checked at a clinic with a microscope and CBCT.

Summary

Cracks are a “hard-to-detect modern problem.” They progress when stress, aging, and biting forces combine.
Early detection plus a “cover-and-protect” strategy can raise the chance of avoiding extraction.
Don’t miss small SOS signs from your teeth. With timely exams and treatment, you can protect your natural teeth for years to come.

Reference

Patel et al. Position statement on longitudinal cracks and fractures of teeth. Int Endod J. 2025;58:379–390.